Senior RNLI lifeguard Martin White spotted the stricken group with RNLI lifeguard Andy Houlder, who called for back-up from RNLI lifeguards Zahli Lowe and Dan Lee.

Mr White said: "Because of the shape of the gully and the size of the swell, it was impossible to get the inshore rescue boat (IRB) or even the rescue board in close enough to pick up the casualties so the only way was to swim in.

"Myself and Andy swam in with rescue tubes, and communicated with Zahli and Dan who were standing off in the IRB. They could see when a set of waves was coming through so we could time our exit in the lull between sets.

"We swam two children out first, with a dad who was helping another child. We dropped them off at the beach 50ft away and returned for the second group.

"We repeated the process with the other three children and one of the adults who was a stronger swimmer helping one of the children.

"Andy returned to help the final adult, dropping them off at the IRB.

"It was a very difficult and long process, made even worse by the time pressures of the incoming tide and a building swell. Thankfully we all know this beach and stretch of coastline very well and were able to read the waves and get them all out safely."

Mr White said lifeguards had just rescued two people in a kayak who had been washed into a nearby cove when they were alerted to the stranded group huddled together on the rocky platform above the gully, which was quickly filling with the incoming tide.

He said the gully has a deep cave at the back, so the only way out was the way the group had gone in.

The RNLI said yesterday was an "extremely busy day" for lifeguards on the beach, with 200 people in the water at Treyarnon.